1. Field of the Invention
This invention relates to a contact image sensor constructed using a plurality of line sensors and, more particularly, to a contact image sensor employed as an original document read-out device employed in turn for example in a copy machine or a facsimile machine.
2. Description of the Prior Art
In the contact image sensor in which sensors are provided in association with an original document, there is a limit to the size along the longitudinal direction of the line sensor. Therefore there is thus known a so-called multi-chip system in which a plurality of line sensors are combined together in order to allow to read out an original document of a larger width.
As the contact image sensor making use of these line sensors, there is known a so-called in-line system in which the line sensors are arranged along a straight line, or a so-called staggered system in which the line sensors are arranged in an interleaved relation with respect to one another. The technique concerning the contact image sensor having these modified line sensor arrangements is described in the Japanese Patent Application Laid Open No. 61-126861.
In the aforementioned prior-art image sensor having two rows of interleaved line sensors, a line memory, for example, need be provided since data readout cannot be performed serially. On the other hand, it is difficult to reduce or enlarge the data size. In the prior-art image sensor having a linear array of the line sensors, problems are presented in connection with the line sensor pitch at the junction points of the adjoining line sensors. It is also difficult to maintain a high degree of bonding accuracy. In the technique of the above prior-art publication, the ends of the line sensors need be processed in a specific manner, while there is similarly presented a problem in connection with the bonding accuracy.